1. Field of the Invention
The present invention relates to a tire air pressure detecting device, a tire air pressure monitoring system, and a tire air pressure transmission method.
2. Background Information
In tire air pressure detecting devices employed in conventional systems for monitoring tire air pressure, limits are placed on the frequency of use of the transmitter with the goal of reducing power consumption. For example, according to the technique disclosed in Japanese Patent No. 4124373, with the vehicle at a stop, the frequency of transmission of the transmitter is set to once every 15 minutes; and if the vehicle speed exceeds 25 km/h, the frequency of transmission is set to once every 54 seconds, thereby keeping transmitting frequency to the lowest limit necessary. Additionally, according to the above publication, transmission of the transmitter may be carried out only when needed through an arrangement whereby after a predetermined period of time has elapsed since the vehicle speed exceeded 25 km/h, transmitting frequency is increased regardless of current vehicle speed when a given pressure fluctuation has occurred.